Endoscope having provision for repositioning a video sensor to a location which does not provide the same cross-sectionally viewed relationship with the distal end

ABSTRACT

An endoscope has a video device arranged at the distal end of the endoscope shaft. The video device is connected by means of a transmission system to a supply unit arranged at the proximal end of the endoscope shaft. The video device is provided with a lens for imaging an object field and an illumination unit. The lens and the image recorder are combined into a video unit which is held in such a movable manner at the endoscope shaft that the outer contour of the cross-section of the video unit lays essentially within the outer contour of the cross-section of the distal end of the endoscope shaft when being introduced into the cavity to be examined. After termination of the introduction procedure, the video unit can be moved in relation to the distal end of the endoscopic shaft beyond the outer contour of the cross-section and/or longitudinal section.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to an endoscope with a video device, whichis arranged at the distal end of an endoscope shaft and is connected bymeans of a transmission system to a supply unit arranged at the proximalend thereof and is provided with a lens, which images an object fieldilluminated by an illumination unit onto an image recorder.

Endoscopes serve to inspect cavities for the purpose of examinationand/or manipulation and have found a great number of applications intechnology and medicine.

Conventional endoscope have a so called image forwarder arranged at thedistal end, which "forwards" the image produced by the lens from thedistal end to the proximal end, where it is examined by means of aneyepiece. In "rigid" endoscopes, the image forwarder is composed ofso-called relay lens sets and in flexible endoscopes of fiber bundles.

Small-sized video image recorders, as by way of illustration CCD chips,have been available for some time. For this reason, it has often beenproposed instead of using an image forwarder, to provide an imagerecorder in the image plane of the lens at the distal end, which isconnected via a transmission system to a supply unit provided at theproximal end. See for example U.S. Pat. Nos. 4,253,447 and 4,261,344, inwhich an "upright" semiconductor image recorder, i.e. an image recorderstanding at a 90° angle to the axis of the endoscope, is arranged in theimage plane of the lens provided at the distal end.

With this kind of an arrangement of the image-recorder chip, however,problems occur, particularly in medical endoscopes, as presentlyimage-recording chips are relatively large compared to the size ofmedical endoscopes. The size of the image-recording chip is especiallyinconvenient in endoscopes which are employed not only for examinationof a cavity, but also for manipulation therein, and have for thispurpose leading from the distal end to the proximal end a main duct,into which, by way of illustration, scissors, tweezers, etc. can beinserted. In order that the image, recording chip, not limit tooseverely the lumen available for the main duct, it has been suggested,by way of illustration, in the German published patent applications 3529 026 and 37 20 624 to arrange the image-recording chip in a"reclining" manner, i.e. parallel to the longitudinal axis of theendoscope.

Except for this special arrangement of the image-recording chip at thedistal end piece of the endoscope, the hitherto proposed "videoendoscopes" differ from conventional ones only in that an imageconducting system (e.g.,--the relay-lens system), is replaced by animage recorder with an electric transmission system arranged thereafter.The construction of the rest of the endoscope however, (that is, thelens arrangement provided at the distal end, the arrangement of theillumination unit and of the ducts, if any, provided for the tweezers,scissors, and the like) remains practically unchanged. Such devicesyield no new examination or treatment possibilities.

Furthermore, the significance of this simple replacing of animage-forwarding system with an image recorder in the state of the artis that the overall lumen of the endoscope, i.e. the requiredcross-section area, continues to be essentially determined by the"addition" of various lumens, which are needed for the unalteredbuilt-in lens, the ducts for the rinse fluids, tweezers, scissors, etc.

The object of the present invention is to design an endoscope having avideo device arranged at the distal end thereof in such a manner thatnew examination and treatment possibilities are yielded and that, inparticular, the overall lumen of the endoscope is no longer determinedby the addition of various, single lumens needed for the individualcomponents, such as lens, rinse and manipulation ducts, illuminationdevice, etc.

The present invention is based on the fundamental concept that there aresubstantially more design possibilities by employing an image-recorderarranged at the distal end of an endoscope than with conventionalendoscopes with "fixed", integrated image-giving systems, regardlesswhether they are provided with a video device or an image-forwarder fortransmitting the image from the distal end to the proximal end.

The above object is achieved in accordance with the present invention bycombining the lens and the image recorder in a video unit, which isconnected to the endoscope shaft in such a moveable manner that theouter contour of the cross-section of the video unit lies essentiallywithin the outer contour of the cross-section of the distal end of theendoscope shaft when introduced into the cavity to be examined followingtermination of the introduction procedure, the video unit is flexible inrelation to the distal end of the endoscope shaft to such an extent thatthe contour of the cross-section and/or longitudinal section of thevideo unit is moved beyond the corresponding outer contour of theendoscope shaft.

In other words, the overall inventive concept consists of no longerdesigning the distal video-examination system as parts fixedly connectedto the endoscope and integrated in the endoscope structure, as is thecase in the state of the art, but rather to combine the lens and theimage recorder and, if need be, the illumination unit for the objectfield of the lens into a video unit, which is moveable as a whole inrelation to the distal end of the endoscope shaft after being introducedinto the cavity to be examined.

This fundamental concept of the present invention can be realized in aso-called rigid endoscope as well as in a flexible endoscope. Theinvented design results in a video-endoscope, which has a number ofadvantages compared to prior art endoscopes having a video devicearranged in a "rigid" manner at the distal end thereof, i.e. fixedlyintegrated in the structure of the endoscope, or the endoscope shaft:

According to an illustrative embodiment hereto, according to which thevideo unit can be swung about an axis, which is parallel to the axis ofthe shaft of the endoscope and eccentric in relation to the front faceof the video unit. The video unit can be "swung out" of the endoscopeshaft, or in the case of an arrangement "before the shaft", out of the"cross-section contour" of the endoscope shaft. This permits not onlyexamination of the cavity under a different angle of vision, but ratherespecially in an endoscope with at least one main duct for rinsingfluids, instruments, etc. has the advantage of improved utilization ofthe available lumen so that the individual lumens, i.e. thecross-section areas of the individual components combined are largerthan the entire cross-section area of the endoscope during introductioninto the cavity:

For this purpose (by way of illustration), the video unit is arrangedduring introduction into and withdrawal from the cavity in such a mannerthat it at least partially covers the duct opening. Followingintroduction into the cavity, the video unit is brought into theexamination position, in which it clears the main duct. In this manner,the cross-section of the endoscope is no longer dictated by addition ofthe required cross-section areas for the duct or ducts and thecross-section area of the lens including the video unit, but rather onlyby the largest lumen of the various single lumens. This advantage isalso yielded by other embodiments, which are described in more detail inthe following section.

In another embodiment the outer diameter of the cross-section of thevideo unit is almost as large as that of the endoscope shaft. Thispermits a comparatively large video unit and thereby the use of a largeand therefore a fast lens, including the use of an image recorder, (suchas, a solid image convertor with a large light-sensitive surface).without the diameter of the endoscope becoming unacceptably large duringthe introduction and withdrawal phase.

The swinging movement of the video unit moveably joined at the distalend of the endoscope can be carried out in various ways, such as bymicro-mechanical actuators, by axes running from the distal to theproximal end, etc. In a preferred embodiment, a pulling cable runningfrom the proximal end to the distal end and back is provided forexecuting the swinging movement according to claim 4 hereto. Thisembodiment has the advantage that the pulling cable can be easily runinto the "unused" areas of the cross-section of the shaft.

The endoscope may be provided with (at least) one transmission duct, inwhich elements generating the swinging movement of the video unit, suchas the previously mentioned (axes also referred to as moving elementshereinafter), including, if need be, the transmission system for thevideo signals, are conducted from the distal to the proximal end.

It is preferable if the transmission duct is connected to the main ductby a slit running in the direction of the axis of the endoscope shaft,which permits removal of the transmission system from the transmissionduct and thereby a separation of the video unit from the actualendoscope. Also, when the outer contour of the cross-section of thevideo unit is adapted to the inner contour of the main duct, such aconnecting slit facilities pushing the video unit forward from theproximal to the distal end, or pushing the unit back. In this way, thevideo unit can, by way of illustration, be replaced with another videounit having, for example, a different focal length and therefore adifferent field of vision, or with a different examination or treatmentsystem, such as a conventional examination optics having a lens andimage conveyor, without needing to remove the endoscope shaft from thecavity.

Because the video according to the invention unit clears at least thelargest part of the main duct, an additional conventional examinationoptics having an image conveying system can also be utilized in the mainduct.

In any case, it is preferable if the transmission duct also serves as aconductor for the element or elements which generate the motion of thevideo unit.

Naturally, the moving element may also be arranged in the main duct.This arrangement is particularly advantageous is a thrust rod serving asa moving element is attached to the video unit eccentrically in relationto the cross-section of the video unit. This embodiment has theadvantage that after pushing the video unit forward beyond the distalend of the shaft, the video unit is brought into a position, in which itclears the greater part of the cross-section of the duct solely bygravity without requiring additional measures.

In a further embodiment of the invention, the contour of thelongitudinal section of the video unit is designed in such a manner thatthere is an edgeless, smooth transition from the maximum cross-sectionof the video unit to the cross-section of the thrust rod, which ensuresthat the video unit can be drawn back into the main duct by simplypulling back the thrust rod thereby permitting easy withdrawal of theendoscope.

In any case, to achieve to optimum exploitation of the available lumenit is advantageous if the moving element, such as the axis or the thrustrod, is hollow and the transmission system is run in the moving element.The moving element may in this event depending on the design of theendoscope (rigid or flexible) be a rigid hollow pipe or a flexible axle.Furthermore, the required "pulling cables" may be provided with anadditional function even in conventional, flexible endoscopes so that,by way of illustration, swinging occurs by additionally turning these"pulling cables". Moreover, a transparent plastic cylinder, whichsimultaneously serves as the light conductor for the illumination light,may be utilized as the element for transmitting the swinging movement.In a further embodiment, in the home position, i.e. in the position inwhich the endoscope can be introduced into or withdrawn from the cavity,the video unit can be swung completely into the shaft, thus providingoptimal protection from damage.

The fundamental concept of the present invention to at least combine thelens and the image recorder into a compact unit, which can be swung "outof the endoscope shaft" following introduction into the cavity,moreover, permits providing not only one swingable unit, but ratherseveral swingable units, of which at least one is a video unit.

It is preferred if the moveable and, in particular, the swingable unitsare arranged in a row at the endoscope shaft at least in the "swung-inposition", as in that case the available lumen is optimally utilized forintroduction and the withdrawal procedures. Furthermore, it is also anadvantage if the units are arranged in a plane which is perpendicular tothe longitudinal axis of the endoscope, following being swung out. Thismay, by way of illustration, be realized by all the units beinginitially arranged in a row and being "swung into the endoscope shaft".After swinging out the units, those units which are arranged behind thefront most unit are pushed forward into their respective, allocatedtransmission ducts by shifting of their moving elements until they arein the same plane as the front most unit. Accordingly, the front unitsmay also be correspondingly drawn back.

Employing video units for all the units permits stereo examination witha relatively large stereo base. Accordingly it would also be possible toperform a more extensive, redundant depth analysis of the cavity to beexamined with more than two video units.

Moreover, only one unit may be a video unit and the other may beprovided with a light emitter. In this manner, by way of illustration,triangulation measuring can be realized.

Furthermore, in addition to the video unit another image giving recordermay be used, by way of illustration, an ultrasonic image recorder.

The fundamental concept of the present invention to combine the lens andthe image recorder including, if need be, the illumination unit into acompact video unit permits not only swinging this video unit, but alsomoving the video unit in relation to the distal end of the endoscopeshaft.

This movement can be oblique, diagonal to the endoscope axis or in thedirection of the endoscope axis. In particular, a telescopicallydesigned moving element may be provided which permits moving the videounit in relation to the distal end after completing the introduction anddrawing back procedures of the unit prior to beginning the withdrawalprocedure. This telescopic moving element may be run in the main duct orin the transmission duct of the shaft.

The fundamental concept of the present invention to create a compactvideo unit, which is not structurally integrated in the endoscope shaft,moreover, permits detaching the video unit from the distal end of theendoscope shaft. In this event, the video unit is only connected to theproximal supply unit via the transmission system in such a manner thatit can be employed as a video probe in the cavity.

In this case, it is an advantage if the video unit designed as a videoprobe can be reattached to the endoscope shaft prior to beginning thewithdrawal procedure. Furthermore, it is preferred if the video probecan be moved forward out of the endoscope shaft (claim 25). A suitabledesign of the "proximal end part" of the video probe even permitsremoving the latter from the hollow organ without an instrument solelyby simply "pulling it out".

Another possible movement of the video unit in accordance with thepresent invention, within the overall inventive concept, is a rotationor a swinging, of the unit about at least one axis, which isperpendicular to the axis of the endoscope shaft. By this means, by wayof illustration, a video unit, which was "initially lying along theshaft", can be "emplaced" following introduction into the cavity.

Furthermore, images of an object to be examined can be taken fromdifferent angles of vision. The different possible movements set forthin the claims may be employed singly or in combination: thus the videounit can, by way of illustration, first be swung out of the endoscopeshaft about an axis, which is parallel to the axis of the endoscope andeccentric in relation to the front face of video unit, and subsequentlymoved in the direction of the endoscope shaft by a telescopicallydesigned moving element. Moreover, moving obliquely or diagonally to theaxis as well as swinging the video unit about an axis, which isperpendicular to the axis of the endoscope, is also contemplatedforeseen. Naturally, these movements can be realized not only bymechanical means. The motions may also be realized with suitablydesigned drive elements, by way of illustration, micro-mechanicallyproduced motors, etc.

The video device, which in accordance with the present invention is setup as a unit separated from the actual endoscope, may be set up in theknown manner. In particular, the image recorders may be arrangedperpendicular to the axis of the endoscope shaft and parallel to theaxis of the endoscope shaft. Furthermore, two image recorder withrespective lenses or one image recorders with two lenses, the image ofwhich can be selectively aimed at the image recorder, may also beprovided. This embodiment permits, by way of illustration, with a 180°lens arrangement, examining a substantially larger object field than ispossible with a conventional lens. So-called straight-vision lenses andso-called oblique-vision lenses may also be used.

As a substantially larger lumen is available for the video unit duringthe introduction and withdrawal procedures due to the fundamentalconcept of the present invention than is the case with conventionalvideo endoscopes, an image convertor may, moreover, be provided for eachcolor take, i.e. for each primary color, with a dichroic deflectionsystem dividing the image of the lens correspondingly.

Furthermore, the output signals of the image-recorder chip may naturallybe transmitted "wirelessly" to the proximal end. Preferable, however,with regard to the size of the construction, the transmission system isrealized with connection lines for the electric and/or opticaltransmission of energy and signals. The individual lines may preferablybe combined to a single connection line which may be employed to pushthe probe forward via the endoscope shaft and to draw back the probe.

The light exit area of the illumination unit may either be arranged"fixedly" to the endoscope shaft or to the video unit.

The fundamental concept of the present invention, moreover, allowsgreater freedom in the design of the illumination unit. Thus one orseveral miniature filament lamps, strobe lamps, light diodes and/orsemiconductor lasers may be provided in the video unit. Naturally,however the illumination light source may also be arranged proximally inthe conventional manner and the light of the illumination light sourcemay be conducted by means of light conductors to the light exit area,where it then emerges. The light conductors may be conventional fiberbundles, or rigid rods, which simultaneously serve as moving elements.

The energy supply of the image recorder and, if need be, of theillumination light source, may be realized by providing opto-electricand/or electro-magnetic transducers in the video unit, which convert theoptical or high-frequency electric, respectively inductively coupled-inenergy into electric energy suited for the image recorder. In reverse,the output signal of the video unit can also be translated by anelectro-optical signal convertor into an optical signal and this signalcan be transmitted to the proximal end.

In a further embodiment of the invention, the end area of the video unitfacing the proximal end tapers and the distal end area of the endoscopeshaft is designed to compliment it. This arrangement permits sure"self-centering" utilization of the video unit or video probe, in theendoscope shaft in the version in which the video unit can be movedbeyond the distal end area prior to beginning the withdrawal procedure,particularly a withdrawal of the video probe without it previouslyhaving been provided on the endoscope shaft.

In yet another embodiment, chambers which can be filled with fluid, areprovided, which upon filling stiffen the endoscope against lateralforces, thus making the flexible endoscope shaft sufficiently rigid thatthe element can be moved transversely to the endoscope shaft. Moreover,partial filling of the chambers results in the endoscope shaft bending.

The video unit may be separated from the endoscope shaft. In addition,by means of an element which can be magnetically influenced, the videoprobe may be positioned independently of the endoscope shaft, forexample, from outside the body.

Because connection lines have plugs, the cross-section of which issmaller than or the same size as the connection cord, which for its partis substantially smaller than the maximum cross-section of the videounit, the video unit may be separated from the shaft by just pulling outthe connection line.

If need be, the video unit can also have a rinsing duct, which by way ofillustration can be employed for cleaning the front lens of theobjective.

The cross-section of the endoscope shaft may, of course, be round likeprior art shafts, whereby the cross-section of the video unit may beround but does not have to be. However, the cross-section of the shaftand the video unit may be designed in the same manner, not round, butrather by way of illustration oval. Clearing the ducts, (for example,tweezer ducts) provided in the shaft can occur by turning the video unit90° in relation to the shaft.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b show a longitudinal section through a first preferredembodiment of this invention.

FIG. 1c a top view of the preferred embodiment of FIGS. 1a and 1b;

FIGS. 1d and 1e depict the moving elements performing the swingingmovement;

FIG. 2 is a longitudinal section through a second preferred embodimentof the invention;

FIG. 3 is a longitudinal section through a third preferred embodiment;

FIG. 4 is a longitudinal section through a fourth preferred embodiment;

FIGS. 5a and 5b show a top view of two versions of a fifth preferredembodiment;

FIGS. 6a to 6c show a sixth preferred embodiment in various positions;

FIG. 7 is a longitudinal section through a seventh preferred embodiment;

FIG. 8 is a longitudinal section through an eigth preferred embodiment;

FIGS. 9a and 9b show a longitudinal section through a ninth preferredembodiment in two positions.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first preferred embodiment of the present invention, inwhich a video unit 1 can be swung about an axis 3, which is parallel tothe axis 2' of the endoscope shaft 2, shown by way of example as a rigidshaft. The endoscope shaft is provided in a known manner with a mainduct 4, which by way of illustration can be used for rinsing withrinsing fluids or into which instruments such as scissors, tweezers,etc. can be inserted. The main duct 4 connects the distal end depictedin FIG. 1, i.e. the end of the shaft 2, which can be inserted into thecavity to be examined, to the proximal end-(not shown), i.e. the endremaining outside of the cavity.

As the axis of rotation 3 of the video unit 1 is arranged eccentricallyin relation to the front face of the video unit, the video unit can beswung from the position depicted in FIG. 1a, in which it is swung intothe main duct 4 of the endoscope shaft, in the direction of the arrow 5into a position, in which it completely clears the main duct 4 (FIG.1b). The dimensions of the video unit 1 and of the shaft and thearrangement of the axis of rotation 3 are selected in such a manner thatthe outer contour of the video unit lies completely within the outercontour of the shaft when the former is in a swung-in state duringexamination in the direction of the longitudinal axis. The "outercontour of the cross-section" of the video unit does not extend beyondthe corresponding contour of the shaft until after a rotation of thevideo unit about the axis of rotation 3. In addition the video unit 1can be moved along an arrow 6, i.e. parallel to the axis 2', permittingnot only an alteration of the object field of the video unit, but alsothe insertion of instruments, such as tweezers, scissors in the mainduct 4, which can be bent to a very great degree at the distal endwithout the bending being hindered by the video unit. Naturally,conventional endoscope optics with a lens and an image transmissionsystem may be used as an additional examination system in the main duct4.

In order to realize the rotation and the movement, an element 7 isattached to the video unit, the element being run in a transmission duct8, which is provided on the outer circumference of shaft 2. In theembodiment depicted in FIGS. 1a to 1c, the movement-transmitting element7 (moving element) is a light conducting rod made of a transparentmaterial. This transparent light conducting rod terminates at a lightexit surface 7' at the front side of the video unit 1. In addition,further light conductors 9, which are "rigidly" integrated in thestructure of the shaft and which by way of illustration may beconventional fiber bundles, are provided in the illustrated embodiment.

FIGS. 1d and 1e show another preferred embodiment of the rotationmovement transmitting element 7. The video unit 1 is moveably joined tothe shaft 2 by means of a shaft 71 in such a manner that it can be swungabout the axis 3. A pulling line 72 running from the proximal end to thedistal end of the shaft 2 and back is provided for turning shaft 71,with two rollers 73 arranged at both sides of the shaft 71 turning thepulling line. Thus moving pulling line 72 by a actuating element (notshown) arranged at the proximal end results in turning the video unitabout the axis 3.

The video unit 1 is provided with a lens 10 image recorder chip 11 (bothschematically depicted in FIGS. 1a to 1c). The image recorder chip 11 isconnectd to a supply unit arranged at the proximal end via theconnection lines 12. In the preferred embodiment depicted in FIGS. 1a to1c, the connection lines 12 are wound about the rod 7. However, themoving element 7 may, naturally, also be designed as a hollow pipe, inwhich the lines 12 and, if need be, light conducting fibers are run.

In the preferred embodiment depicted in FIGS. 1a to 1c, the video unit 1with the lens 10 and the image recorder 11 provided therein as well asthe light exit area 7' of an illumination unit can be swung out of aposition, in which the video unit is essentially arranged at the side ofthe endoscope shaft 2, into the endoscope shaft 2, which is provided forthis purpose with a corresponding projection 21, which is depicted darkin FIG. 1c.

Naturally, the video unit may however be also be arranged before theendoscope shaft 2 and accordingly swung before the endoscope shaft 2.This is shown in a representation corresponding to FIG. 1a in FIG. 2, inwhich moreover the same designations are used for the same elements asin FIG. 1 thus obviating another description.

The preferred embodiment depicted in FIG. 2 also differs from thepreferred embodiment illustrated in FIG. 1 in that the image recorder 11is not arranged perpendicular to the longitudinal axis 2' of theendoscope, but rather parallel thereto. Correspondingly a deflectionprism 13 is provided, which deflects the image of the lens 10, which,without the intention of limiting the scope and spirit of the presentinvention, is a so-called "straight-vision lens" in both preferredembodiments, onto the light-sensitive area of the image recorder 11. Aso-called oblique-vision lens may, of course, also be employed.

By virtue of the fundamental concept of the present invention to swingthe video unit 1 before or in the main duct 4 during introduction andwithdrawal of the endoscope, a substantially larger lumen is availablefor the video unit than in conventional video endoscopes. As a result,not only larger lenses and image convertors can be employed than inconventional video endoscopes, but also a construction, in which threeimage recorders for the three primary colors, can be provided.

FIG. 3 shows a corresponding preferred embodiment with the three imageconvertors 11₁ to 11₃. A dichroic image element 14 divides the light ofthe lens 10 into the three image convertors 11₁ to 11₃. Other than that,the third preferred embodiment depicted in FIG. 3 corresponds to thepreferred embodiment shown in FIG. 2.

In the preferred embodiments described in connection with FIGS. 1 to 3,only one video unit 1 is provided, which accommodates the lens 10, theimage recorder 11 and, if need be, the light exit area 7' of anillumination unit, and which is moveable following introduction into thecavity as a whole in relation to the distal end of the endoscope shaft2. Naturally, more than one video unit can also be provided:

FIG. 4 shows a fourth preferred embodiment, in which the two video units1' and 1" are provided, the moving elements 7' and 7" of which are runcoaxially in a transmission duct 8. Other than that, the elementsdepicted in FIG. 4 with the same designations as in the previous figurescorrespond to the elements described, thus obviating anotherdescription.

However, the moving elements 7 for the individual video units can, ofcourse, also be run not coaxially but--as shown in a top view in FIG.5--in different ducts 8' and 8". If at least one of the two video units1 or 1' is designed in such a manner that it can be moved in thedirection of the longitudinal axis of the endoscope shaft, afterswinging out the two video units 1' and 1" can be arranged in the sameplane perpendicular to the longitudinal axis of the endoscope. In thismanner, by way of illustration, a stereoscopic image is possible.

Naturally, in the preferred embodiments shown in FIGS. 4 and 5 it is notnecessary that both units are video units. By way of illustration, oneof the two units 1', or 1", may accommodate a light source as, by way ofillustration, a miniature light bulb, a light diode or a laser diode.Furthermore, one of the units may also accommodate another image givingrecorder, as by way of illustration, an ultrasound array. Finally,another endoscopic measuring system, such as two laser diodes, may beintegrated in units 1' and 1" and the examination may be conducted withan examination unit, a conventional optical system 1"' or a video unit,introduced into the central main duct 4 (FIG. 5b).

In the preferred embodiments shown in FIGS. 1 to 5, the video unit 1 canbe swung about an axis 3, which is parallel to the axis 2' of theendoscope shaft 2 and eccentric in relation to the front area of thevideo unit 1. In addition, if need be, a movement in the direction ofthe axis 3 may occur.

FIGS. 6a to 6c depict a sixth preferred embodiment of the presentinvention, in which the video unit 1 can be swung about an axis 20,which is perpendicular to the axis 2' of the endoscope shaft 2.Furthermore, in this preferred embodiment, the video unit 1 is providedwith two lenses 10' and 10", the optical axes of which enclose a 180°angle, as well as two image recorders 11' and 11".

In the "0° position" shown in FIG. 6a the video unit 1 is folded beforethe endoscope shaft 2, whereas in the 180° position shown FIG. 6c itlies parallel to the endoscope shaft 2 and, by way of illustration,clears the opening of a duct 4, which is not shown in more detail, inthe endoscope shaft. FIG. 6b shows corespondingly the 90° position, inwhich an examination of the lateral area, such as of an operation area,is possible.

In addition, the video unit may also be swung about an axis 3, which isparallel to the axis 2', according to the preferred embodiments shown inFIGS. 1 to 5.

FIG. 7 depicts a seventh preferred embodiment, in which the video unit 1is attached via a ball-and-socket joint 31 to a telescope carrier formedby one of the two elements 32 and 33. The telescope carrier for its partis again moveably joined to the distal end of endoscope shaft 2. Bymeans of this embodiment version, video unit 1 can be pushed forwardbeyond the distal end of the endoscope shaft 2, thereby permitting moreextensive examination. Moreover, the ball-and-socket joint 31 providedat the front end of the telescope, permits examination under differentangles of vision.

All the above described preferred embodiments have in common that thevideo unit 1 remains connected via suitable elements to the endoscopeshaft 2 during movement.

Naturally, the video unit 1 may also be designed in such a manner thatin a certain position it can be separated from the endoscope shaft 2 orthat it may be freely inserted into the duct 4, with the connection tothe proximal end being retained by a thrust element.

FIG. 8 shows schematically a preferred embodiment, in which the videounit 1 is connected to the endoscope shaft only via a connection line 12and can be moved by it over the distal end of the shaft in such a mannerthat the video unit can be employed as a video probe. If the proximalend of the video unit 1 and the distal end of the endoscope shaft 2 aredesigned in a complimentary manner, the video probe (video unit 1) afterhaving been drawn back by means of the line 12, can be easily insertedinto the corresponding recess in the endoscope shaft 2 once more.

FIGS. 9a and 9b show a preferred embodiment, in which the video unit 1is only inserted in the main duct 4 of shaft 2 in such a manner that thevideo unit can be moved therein. A thrust rod 7', which is eccentric inrelation to the cross-section of the video unit and which is alsoarranged in the main duct 4, is provided at the video unit 1. Thisversion has the advantage that after the video unit has been movedbeyond the distal end, the video unit is brought into a position, inwhich it clears the largest part of the cross-section of the duct,without further measures, solely due to gravity (FIG. 9b). In theillustrated preferred embodiment, the contour of the longitudinalsection of the video unit 1 is designed to provide an edgeless, smoothtransistion from the maximum cross-section of the video unit 1 to thecross-section of the thrust rod 7'. In this way, it is ensured that bysimply drawing back the thrust rod, the video unit can be drawn backinto the main duct so that in the position depicted in FIG. 9a, in whichthe video unit 1 is arranged in the main duct 4, easy withdrawal of theendoscope is possible.

In the previous section, the present invention has been described usingpreferred embodiments without the intention of limiting the scope andspirit of the present invention, within which the most varied anddifferent modifications are possible.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample, and is not to be taken by way of limitation. The spirit andscope of the present invention are to be limited only by the terms ofthe appended claims.

In particular, the different possible movements described in thepreferred embodiments can be combined with each other:

Thus, a telescopic moving element, at the end of which the video unit isjoined in such a manner that it can be swung about an axis, which isparallel to the axis of the endoscope shaft 2, and rotated about anaxis, which is perpendicular thereto, may be provided in thetransmission duct 8. Furthermore, a possible means of moving the videounit in one or several directions may be provided, which enclose anangle unequal to 0° with the axis of the endoscope shaft, thus toprovide an "oblique movement". Furthermore, the endoscope shaft may bedesigned in such a manner that it can be folded open or it may beprovided with a slit so that the video unit can be withdrawn from theshaft together with the connection line attached thereto. For thispurpose, a slit may also be provided between the main duct 4 and thetransmission duct 8. The afore-described possibilities, of course, mayalso be employed to the same degree in rigid and flexible endoscopes. Inflexible endoscopes it may be necessary "to stiffen" the endoscopes bymeans of fluid chambers, which can be so that they become semi-flexiblein order to realize the various possible movements.

Furthermore, it may be an advantage to compensate the distal turning inthe video representation unit arranged at the proximal end by means ofprior art image processing methods so that, by way of illustration, "up"and "down" are not reversed for the observer when the unit is swung. Ifneed be, mechanical compensation by turning the image recorder may alsooccur.

What is claimed is:
 1. An endoscope comprising an elongated shaft having a distal end and a proximal end, an illumination unit and a video unit arranged at the distal end of said shaft and connected by a transmission system to a supply unit arranged at the proximal end of said shaft, said video unit comprising a lens adapted to acquire images of an object field illuminated by said illumination unit and at least one image recorder which is adapted to record and transmit images acquired by said lens, said video unit being movable between a first position adjacent the distal end of said shaft, in which an outer contour of a cross section of said video unit lies substantially within an outer contour of a cross section of said distal end of said shaft during introduction and withdrawal of said endoscope into and out of a cavity to be examined, and at least a second position in which the outer contour of the cross section of said video unit lies substantially without the outer contour of a cross section of the distal end of said shaft after completion of the introduction of said endoscope into said cavity, and actuating means for causing said video unit to move between said first position and at least said second position.
 2. An endoscope according to claim 1, wherein said video unit is adapted to be rotated about an axis which is parallel to a longitudinal axis of said endoscope shaft and eccentric in relation to the front face of said video unit.
 3. An endoscope according to claim 2, wherein the outer diameter of the cross-section of said video unit is nearly as large as that of said endoscope shaft.
 4. An endoscope according to claim 2, wherein said video unit is adapted to be rotated by means of a pull cable running from the proximal end to the distal end and back, the pulling of which is guided from axial to lateral via a distal roller system.
 5. An endoscope according to claim 1, wherein said endoscope shaft has a main duct which connects the distal end with the proximal end, and said video unit at least partially covers the opening of said duct during the introduction and withdrawal of said shaft into and out of said cavity in said first position, and clears said main duct in said second position.
 6. An endoscope according to claim 5, wherein said endoscope shaft has a transmission duct adapted to receive said actuating means and transmission system.
 7. An endoscope according to claim 6, wherein said transmission duct is connected to said main duct by a slit running in the direction of a longitudinal axis of said endoscope shaft.
 8. An endoscope according to claim 6, wherein said outer contour of the cross-section of said video unit conforms to the inner contour of said main duct in such a manner that the former can be pushed forward through said main duct into an examination position at said distal end of said shaft, and pulled back to the proximal end.
 9. An endoscope according to claim 8, wherein said transmission duct is adapted to serve as a guide for said actuating means.
 10. An endoscope according to claim 8, wherein said actuating means comprises a thrust rod coupled to said video unit eccentrically in relation to a cross-section of said video unit.
 11. An endoscope according to claim 10, wherein a longitudinal contour of said video unit has an edgeless, smooth transition from the maximum cross-section of said video unit to the cross-section of said thrust rod.
 12. An endoscope according to claim 11, wherein said thrust rod can be moved within said main duct.
 13. An endoscope according to claim 12, wherein said actuating means is hollow, and said transmission system is arranged inside said actuating means.
 14. An endoscope according to claim 13, wherein said actuating means is a rigid hollow pipe or a flexible axle.
 15. An endoscope according to claim 1, wherein said video unit in said first position is disposed within said shaft.
 16. An endoscope according to claim 1, wherein said illumination unit is movable.
 17. An endoscope according to claim 16, wherein said illumination and video units are rotatable.
 18. An endoscope according to claim 16, wherein said illumination and video units are arranged behind each other along a longitudinal axis of said endoscope shaft.
 19. An endoscope according to claim 18, wherein said illumination and video units are adapted to be disposed in a common plane which is perpendicular to the longitudinal axis of said endoscope after being swung out.
 20. An endoscope according to claim 19, further comprising a second movable video unit, whereby stereo imaging is possible.
 21. An endoscope according to claim 16, further comprising a light transmitter for triangulation measuring.
 22. An endoscope according to claim 16, wherein said video unit is provided with another image-giving recorder.
 23. An endoscope according to claim 1, wherein said video unit can be moved in a direction which is parallel to a longitudinal axis of said endoscope.
 24. An endoscope according to claim 1, wherein said actuating means comprises a telescopically designed moving element adapted to move said video unit along the direction of a longitudinal axis of said endoscope.
 25. An endoscope according to claim 1, wherein said video unit can be detached from the distal end of said endoscope shaft, said video unit remaining connected only to the proximal supply unit via said transmission system whereby said video unit is adapted to be used as a video probe, and is adapted to be reattached to the distal end for withdrawal of said endoscope form said cavity.
 26. An endoscope according to claim 25, wherein said video unit is adapted to be pushed forward out of said endoscope shaft.
 27. An endoscope according to claim 26, wherein said video unit is adapted to be rotated, about at least one axis which is perpendicular to a longitudinal axis of said endoscope shaft.
 28. An endoscope according to claim 1, wherein said image recorder is arranged perpendicular to a longitudinal axis of said endoscope shaft in said video unit.
 29. An endoscope according to claim 1, wherein said image recorder is arranged parallel to a longitudinal axis of said endoscope shaft in said video unit.
 30. An endoscope according to claim 1 wherein said video unit further comprises a second image.
 31. An endoscope according to claim 1, wherein said image recorder has two lenses, the image of which can be selectively aimed at said image recorder.
 32. An endoscope according to claim 1, wherein said video unit further comprises a plurality of image convertors, onto which a dichroic deflection system steers light from said lens.
 33. An endoscope according to claim 1, wherein said transmission system is provided with at least one connection line for electrical and/or optical transmission of energy and signals.
 34. An endoscope according to claim 1, wherein electric signal lenses, energy lines and light conductors are combined into a single connection line.
 35. An endoscope according to claim 34, wherein said connection line is adapted to control movement of said video unit.
 36. An endoscope according to claim 1, wherein a light exit area of the illumination unit is provided at said endoscope shaft.
 37. An endoscope according to claim 36, wherein said light exit area of said illumination unit is provided at said video unit.
 38. An endoscope according to claim 37, wherein said illumination unit is provided with an illumination light source arranged in said video unit.
 39. An endoscope according to claim 37, wherein said illumination unit is provided with an illumination light source arranged at said proximal end, and light conductors adapted to conduct light from said light source to said video unit.
 40. An endoscope according to claim 1, wherein said video unit is provided with transducers adapted to supply energy to the image recorder and to said illumination light source, said transducers being one of: opto-electrical and electromagnetic.
 41. An endoscope according to claim 1, wherein in said video unit comprises an opto-electrical signal converter for the output signal of said image recorder.
 42. An endoscope according to claim 26, wherein an end area of said video unit, which is facing the proximal end of said endoscope shaft has a tapered contour, and the distal end area of said endoscope shaft is designed in a complimentary manner.
 43. An endoscope according to claim 42, wherein said endoscope shaft is flexible and is provided with chambers, adapted to be filled with fluid, whereby said endoscope shaft becomes rigid against lateral forces upon being filled.
 44. An endoscope according to claim 1, wherein said endoscope shaft is adapted to be folded open along the longitudinal axis thereof so that said video unit can be separated from said endoscope shaft.
 45. An endoscope according to claim 1, wherein said endoscope shaft is provided with a longitudinal slit that said video unit can be separated from said endoscope shaft.
 46. An endoscope according to claim 1, wherein said video unit comprises a magnetically influenced element for contactless positioning of said video unit independent of said endoscope shaft.
 47. An endoscope according to claim 34, wherein said connection line is provided with plugs, the size of a cross-section of which is no greater than a cross section of the connection lines, which are substantially smaller than the maximum size of a transverse cross-section of said video unit.
 48. An endoscope according to claims 1, wherein an optical axis of said lens of said video unit is disposed at an angle with the axis of said endoscope shaft.
 49. An endoscope according to claim 1, wherein said video unit is provided with at least one rinsing duct to rinse said lens.
 50. An endoscope according to claim 1, wherein an examination unit with image forwarders can be utilized instead of said video unit.
 51. An endoscope according to claim 50, wherein said examination unit is adapted to be inserted in said main duct.
 52. An endoscope according to claim 1, wherein a crosssection of said shaft and a cross section of said video unit are oval and said video unit is adapted to be rotated 90° about a longitudinal axis of said shaft. 